This invention relates to a combinatorial weighing and counting method and apparatus. More particularly, the invention relates to a combinatorial weighing and counting method and apparatus which includes steps of setting a target weight or target number for articles belonging to a plurality of different categories (hereafter the target weight and target number will be referred to as the target value where appropriate), and obtaining a batch of the collected articles wherein the total value (weight or number) of the articles classified by category is equal to the target value set for that category, or is closest to the target value within preset allowable limits.
A combinatorial weighing method known in the art includes steps of weighing articles which have been introduced into the weighing hoppers of a plurality of weighing machines, selecting the combination of weighing machines that gives a weight total equal to a target weight or closest to the target weight within preset allowable limits, discharging only the articles held by the hoppers of the selected weighing machines, replenishing the emptied hoppers with articles, finding the next combination, and repeating the foregoing process to permit highly accurate weighing to continue in automatic fashion.
There is also known a combinatorial counting method which includes the steps of weighing articles which have been introduced into the weighing hoppers of a plurality of weighing machines, dividing each weight value by the weight of each article (i.e., the unit weight thereof) to obtain the number of articles introduced into each weighing machine, adding combinations of the article numbers, selecting the combination of weighing machines that gives a total number equal to a target number or closest to the target number within preset allowable limits, discharging only the articles held by the hoppers of the selected weighing machines, replenishing the emptied hoppers with articles, finding the next combination, and repeating the foregoing process to permit highly accurate counting to continue in automatic fashion.
These conventional combinatorial weighing and counting methods are applicable to articles of a single variety only or, at best, to a mixture of different articles where the ratio of the articles in the mixture is predetermined. Accordingly, it has not been possible with the conventional methods to obtain a batch of articles of a plurality of categories wherein each category of articles exhibits a predetermined weight or article number of great accuracy.